Open Radar

 
Summary:
The OS X mouse cursor flickers when it is rolled over certain elements within a PDF document that has been opened within Safari [i.e. the embedded viewer]. If the Safari window does not have focus, then the cursor does not flicker when rolled over those same elements.

Steps to Reproduce:
Open a PDF document in Safari with the embedded viewer. In other words, don't download the PDF and open in in Preview, let the PDF open within Safari. For example open: http://thinkslimmer.files.wordpress.com/2012/07/carinos-nutrition-guide.pdf

Expected Results:
I expect the mouse cursor to have a consistent state and appear as though it's not having a seizure. 

Actual Results:
The cursor acts like its having a seizure and flickers in and out. The speed varies depending on how fast I move the cursor over the elements within the PDF document. The cursor does not appear to change to another type such as shown for the text selection.

Regression:
This is a new problem with either OS X 10.8 and/or Safari 6.0. This problem was not present on the last version of OS X 10.7 or the previous version of Safari.

Notes:
Perhaps this is related to bug ID 11968141 which is about a flickering cursor on the screen grab reticule. The flicker behavior in this issue appears the same as in that bug, so perhaps there is an underlying API that's the problem. 

However, the problem is not present on the same PDF when downloaded and opened in preview. When opened in Preview the mouse cursor is always the text selection type, whereas when the PDF is opened within Safari the mouse is always the standard pointer. Perhaps the flicker is the transition between pointer and text selector types, but there is a bug because the text selector type cursor will never appear, even when text is selected in the embedded viewer.